Question

Evaluate the determint of the matrix
|1 2|
|-2 -1|
this is one matrix

Answer 1

|A|=3

Answer 2

may you explain ?

Answer 3

for 2 by 2 matrix

Answer 4

\[\left[\begin{matrix}1 & 2 \\ -2 & -1\end{matrix}\right]=1*(-1)-(-2)*2=-1+4 =3\]

Answer 5

thanks can we do 1 more?

Answer 6

yes

Answer 7

but after the medal :p

Answer 8

know what post new question this way i get one more hehe

Answer 9

oh sorry ...and i will